Building a Pressure-Sensitive, Multi-Point TouchScreen?

sonamchauhan asks: "I'd like advice on building (yes, building) my own low-res touchscreen. The reasons for 'build' instead of 'buy' are: 1) to have it sense pressure (pressure sensing is quite expensive) and 2) to have it sense multiple points of contact simultaneously (which is a useful thing). Back in 1985, researchers at U.Toronto built (PDF file) a touch-tablet (not a touch-screen) that fulfilled both requirements (pressure-sensitive and multi-touch) and used only basic electronics: lots of diodes, A/D convertors, etc. Some 17 years later, it should be possible to build a touch-screen using the same techniques (possibly using layers of transparent conductive and insulating paint for the sensor paths.) Any comments? Some other links: a Microsoft paper (PDF file) describing a touch sensor painted onto a mouse, a basic FAQ on current touchscreen technology, and a slashdot thread that discussed building touchscreens (these links don't address pressure or multi-touch though)."

Comments

MTC TacTex pressure-sensative pads

[Robbat2]

From a whole lot of research I have been involved in, for a while we worked with a company, TacTex Controls Inc.

They have a pressure sensative pad and system you can use, the MTC Express (http://www.tactex.com/prodMTC.htm), however, that is not where you would be interested directly.

Their technology uses fiberoptics in a rubber pad with a small controller. There is a lot of research in integrating their technolgies into other things (a prototype of a complete pressure sensative suit was discussed at one stage).

It fufills your requirements quite well.
256 levels of pressure for each region of the pad independently.

The MTC Express pad had only a DB9 serial connection, and needed a power input as well. However, the OEM material and controllers were a lot more flexible in usage.